Transfer RNAs Mediate The Translational Regulation In The Rapid Adaptation Of Escherichia Coli To Oxidative Stress

Oxidative stress which involved in many physiological and pathological processes,has always been a hot topic in biology for decades.When dealing with sudden oxidative stress,cell must maintain homeostasis through a series of regulatory mechanisms,and translational systems can respond promptly to such environmental or endogenous changes.For example,eukaryotic cells are able to manipulate their tRNA molecules to suppress translation,mainly in a reversible manner.Unlike the well-studied translational responses to oxidative stress in eukaryotic systems,little is known about how prokaryotes respond rapidly to oxidative stress in terms of translation.In this study,we measured protein synthesis from the entire Escherichia coli proteome and found that protein synthesis was severely slowed down under oxidative stress.With unchanged translation initiation,this slowdown was caused by decreased translation elongation speed.We further confirmed by tRNA sequencing and qRT-PCR that this deceleration was caused by a global,enzymatic downregulation of almost all tRNA species shortly after exposure to oxidative agents.In short,the E.coli nonspecifically,irreversibly,and enzymatically degrade tRNAs to block protein synthesis.And interestingly,elevation in tRNA levels accelerated translation and protected E.coli against oxidative stress caused by hydrogen peroxide and the antibiotic ciprofloxacin.Our results showed that the global regulation of t RNAs mediates the rapid adjustment of the E.coli translation system for prompt adaptation to oxidative stress.Our results provide a new understanding of the global adjustments to the entire translation system during bacteria stress adaptation.This mechanism may also be involved in the development of bacterial antibiotic resistance.